Ректорат УДУНТ

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The Application of Fuzzy Sets Theory in the Methodological Approach to Assessing Personnel Risks of an Enterprise
(Alfred Nobel University, Dnipro, 2024) Harmider, L.; Korotka, Larysa I.; Bazhan, Serhii P.; Aniskevich, D.
ENG: The main idea of this paper is the substantiation of the methodological approach to the assessment of personnel risks of enterprises based on the application of the fuzzy logic apparatus in order to identify the problems of personnel risk management and provide appropriate recommendations for their solution. The methodological basis of the study is the classic provisions and fundamental works of foreign and domestic scientists, statistical data, the results of our research into the problems of assessing personnel risks of enterprises. The methods of fuzzy set theory, comparative analysis, scientific abstraction, generalization of scientific experience of modern theoretical research, system-complex approach were used. The study proposed a methodological approach to assessing the level of personnel risks of an enterprise; numerical experiments were conducted on the basis of a group of construction equipment manufacturers. Analysis of the results of assessing the level of personnel risks of enterprises made it possible to identify the problems of managing personnel risks at enterprises. The proposed methodological approach to assessing the level of personnel risks of enterprises based on the apparatus of fuzzy logic allows, in contrast to existing ones, to integrate the consideration of both qualitative and quantitative indicators when assessing the level of personnel risks and personnel movement indicators and to significantly increase the efficiency of decision-making under conditions of uncertainty and reduce costs in the event of adverse situations. Using in practice a methodological approach to assessing the level of personnel risks of enterprises based on the apparatus of fuzzy logic allows us to analyze the level of personnel risk as a multi-element object that is closely related to the structured functioning of the enterprise and its capabilities; and expands the original basis for conclusions, which provides a more accurate assessment of the level of personnel risk and making a reasoned decision to reduce its level.
Bifurcation State and Rational Design of Three-Layer Reinforced Compound Cone-Cylinder Shell Structure under Combined Loading
(Publishing House “Akademperiodyka”, Kyiv, 2023) Gristchak, V. Z.; Hryshchak, D. V.; Dyachenko, N. M.; Sanin, A. F.; Sukhyy, Kostyantyn M.
ENG: An analytical-numerical approach to solving the problem of state bifurcation in terms of local and overall stability of a three-layer cone-cylinder shell structure discretely supported by intermediate rings, in particular of modern launch vehicles, under static combined loading by external pressure, axial forces, and torque is proposed in the paper taking into account the stiffness parameters of the intermediate rings in the plane of the initial curvature and for torsion. Corresponding solving equations for the problem are ordinary differential equations of the sixth order (for a cylindrical compartment with constant coefficients and for a conical one with variable coefficients along the axial coordinate). Differential relations that determine the conditions of conjugation through the intermediate ring are used. For the numerical solution, the finite difference method is used with central finite differences of the third and second order at the inner points of the shell determination segments and at its ends, respectively, and the second order differences with one step backward or forward at the conjugation points through the ring. The agreement of the calculation results with the known data for three-layer conical and cylindrical shells is shown, as well as in the limiting case, it is done when passing to a single-layer compound cone-cylinder structure. For the considered class of cone-cylinder shell structures, boundary surfaces are constructed that separate the stability region of the structure being under study, depending on the geometric and stiffness parameters of the compartments, reinforcing elements, and the external load condition. The external load effect on the parameter of the post-critical wave formation for the structure under investigation is studied, providing the visualization of the deformation behavior. The analysis of the calculation results has shown that this approach to solving the problem of bifurcation and equistability of the compound structure compartments in relation to the local and overall forms of protrusion allows choosing rational geometric and stiffness parameters of the shell components and force elements in terms of improving the weight characteristics of the structure.
Carbon Materials for Electrically Conductive Concrete
(EDP Sciences - Web of Conferences, France, 2024) Savytskyi, Mykola V.; Sukhyy, Kostyantyn M.; Savytskyi, Oleksandr M.; Babenko, Maryna; Shevchenko, Tetyana
ENG: In recent decades, the direction of building materials science related to the creation of Smart Concretes has been rapidly developing. Smart Concretes, in addition to the functions of a structural material, also perform other functions that are related to their new properties. Among the large number of Smart Concretes, it is necessary to highlight Electrically Conductive Smart Concrete. This type of concrete is obtained by adding conductive fillers to the concrete mixture. Among them, carbon materials are the most promising in terms of their properties. Despite the large number of conducted studies of conductive fillers and conductive concrete, there is still no generalization and systematization of them. In addition, there are no standards for testing the conductive properties of both fillers and concretes. Therefore, the authors aimed to systematize data on Electrically Conductive Smart Concrete, as well as electrically conductive carbon fillers. A method for testing the electrical conductivity of Carbon Nanomaterials (CNMs) as fillers for Electrically Conductive Concrete is proposed. Approbation of the proposed method was carried out by determining the electrotechnical indicators of carbon fillers, such as coke breeze and carbon black.
Carbon Plastics for Reusable Hypersonic Flight Vehicles
(Ukrainian State University of Chemical Technology, Dnipro, 2024) Kazakevich, M.; Husarova, I.; Kazakevich, V.; Manko, T.; Khoroshylov, V.; Kozis, K.; Osinovyy, G.; Sukha, Iryna V.; Zaichuk, Oleksandr V.
ENG: The development of hypersonic unmanned aerial vehicles (UAVs) for aerospace systems presents ambitious challenges for scientists and engineers. Extreme flight conditions, such as ultra-high speeds and significant aerodynamic heating, necessitate the creation of new materials capable of withstanding such loads. One of the most promising materials for constructing hypersonic UAVs is carbon fiber-reinforced polymer based on bisphenol nitrile. This material exhibits high thermal resistance, chemical stability, and excellent mechanical properties. Utilizing bisphenol nitrile combined with carbon fibers has enabled the production of composite materials that can operate at temperatures exceeding 300 оC, far surpassing the capabilities of traditional polymer matrices. To assess the suitability of the developed carbon fiber-reinforced plastic for hypersonic UAV applications, comprehensive studies of its physical, mechanical, and thermal characteristics were conducted across a wide temperature range from 20 to 300 оC. The obtained results provided a detailed characterization of the composite and allowed for comparisons with other high-temperature composite materials. The developed carbon fibre-reinforced plastic based on bisphenol nitrile binder shows great promise for constructing hypersonic UAVs. Its high thermal resistance, combined with excellent mechanical properties, makes it suitable for use in the extreme temperature conditions typical of hypersonic flight.
The Concept of Anthropotechnics in the Social and Humanitarian Dimension
(Український державний університет науки і технологій, Дніпро, 2024) Bazhan, Serhii P. ; Chernova, Nataliia S.
ENG: Purpose. This research defines the conceptual foundations of anthropotechnics as a science that studies modern processes of interaction between humans and technologies in the socio-humanitarian dimension. Theoretical basis. The authors use the method of anthropological analysis, which allows generalizing the approaches of anthropotech-nics in the socio-cultural context in the "human-technology" system. Originality. Based on the results of the re-search, the understanding of the essence of anthropotechnics as a science that studies human interaction with tech-nologies and technical systems has been clarified. The idea of implementing anthropotechnical approaches to the management of the educational process gained further development, in particular in the context of practical training of applicants for education, distance learning, and dual education forms. The concept of professional activity and professional self-realization of the individual is taken into account, and promising directions in the development of anthropotechnics in the context of the application of artificial intelligence are determined. Conclusions. Considering anthropotechnics in a philosophical and sociocultural dimension is an important approach to understanding the in-teraction of technologies, people, and society as a whole, where technologies affect human perception of the world and interaction with it. The range of approaches chosen by the authors, the disclosure of their principles and catego-ries allows for considering the object of this research – anthropotechnics as a modern science – in a multifaceted and holistic way, to interpret the results of the research based on the use of the basic categories of approaches: a person, equipment, technology, activity, development, personality, system.
Coordinated Control of the Composition of 01yut Steel and Deformation Processing Modes to Achieve Specified Mechanical Properties
(National Metallurgical Academy of Ukraine, Ukrainian State University of Science and Technologies, Dnipro, 2024) Velychko, A. G.; Kamkin, V. Yu.; Proidak, Yurii S.
ENG: Purpose: to investigate the influence of the chemical composition of steel on the output from the chipboard and to establish rational parameters of deoxidation and deformation to ensure the specified values of mechanical properties. Methods: physicochemical modeling, thermodynamic calculations, experimental studies. Results: the carbon content and the degree of oxidation of the semi-finished product from the electric furnace for further vacuum treatment to obtain low-carbon steel were determined. With an increase in the oxygen flow rate supplied to the chipboard and exceeding the value required for the stoichiometry of fuel combustion reactions, the oxidation of the semi-finished product increases. To avoid the formation of calcium silicates, it is necessary to have an active oxygen content below 2.5 ppm, which is ensured by the residual content of dissolved aluminum in steel of 0.025-0.027%. Scientific novelty: The use of complex deoxidizers in steel production allows using the synergistic effect of the joint deoxidizing action of deoxidizing elements. The use of the methodology of physicochemical modeling made it possible to effectively solve the problem of predicting the properties of steel. To study the influence of modifier elements, as well as the main alloying components, a number of parameters characterizing the state of the alloy as a whole (Zу, d) were calculated. Based on information on the significant influence of the chemical composition of the steel on its properties, a database of 150 compositions was prepared to determine the optimal composition of ultra-low-carbon steels of the 01ЮТ, 01ЮТА type by the method of physicochemical modeling. Based on the calculations, the concentrations of elements for steels of the 01ЮТ and 01ЮТА grades were selected.
Design of Proactive Management System for Residential Buildings by Using Smart Equipment
(TECHNOLOGY CENTER PC, Kharkiv, 2023) Savytskyi, Mykola V.; Shekhorkina, Svitlana; Bordun, Maryna; Babenko, Maryna; Tsyhankova, Svitlana; Spyrydonenkov, Vitalii; Savytskyi, Oleksandr M.; Rabenseifer, Roman
ENG: This study's object is an energy efficiency of residential sector. The work is aimed at solving the task to improve the energy efficiency of the housing sector by devising technical solutions for monitoring and managing energy consumption and microclimate parameters of buildings. The proposed proactive management system for residential buildings consists of multi-sensors measuring CO2, temperature and humidity, smart meters of heat and electricity consumption, and smart plugs. The equipment is combined into single system through an integration controller with remote user access through an interactive web interface. A feature of the technical solution is the ability to collect, process, visualize, and archive data on the consumption of energy, as well as on the key parameters of the microclimate of residential premises. The advantages of the system are its flexibility due to the possibility of integrating additional devices during operation, as well as the use of standard communication protocols, which enables the interchangeability of component elements. The implementation and testing were carried out under the conditions of a real pilot site. The use of the system in practice confirmed the efficiency and stability of the operation, making it possible to obtain data on the parameters of energy consumption and microclimate and devising recommendations for reducing energy consumption at the pilot site. It was established that the microclimate meets the requirements of the standards (air temperature is about 22 °С while relative humidity does not exceed 60 %). Decrease in energy consumption can be achieved by reducing the temperature of the heat carrier in the absence of residents, as well as by considering the influence of weather conditions. During periods of residents’ activity, an excess of the permissible level of CO2 was recorded, therefore, automatic ventilation systems should be provided in the apartments.
Determining the Energy Efficiency Indicators of the Diesel Train DPKr-2 and the Rail Bus 620M Based on Traction Calculations Using the Numerical Method of Solving the Equation of Train Movement
(MATEC Web of Conferences, 2024) Kapica, Mihajlo; Bobyr, Dmytro V.; Hryshchenko, Mykola A.; Kyslyi, Dmytro M.; Desiak, Andrii Y.
ENG: The purpose of the article is to compare the technical and energy parameters of the diesel train DPKr-2 and the railbus 620M based on traction calculations using mathematical modeling when solving the train movement equation. The mathematical model of the train is adapted to determine the movement parameters of the specified rolling stock units according to different variable phase coordinates for different movement modes. To achieve this purpose, the authors used methods of system analysis, nonlinear programming, and numerical methods for solving differential equations. The accuracy of the calculations was verified using simulation modeling methods and compared with experimental data. To analyze the results, the obtained indicators of traction calculations – technical speed and specific consumption of diesel fuel – were compared. As a result of the comparison, the specific fuel consumption per ton-kilometer meter, a significant saving of energy resources is observed. Comparative specific fuel consumption per passenger-kilometer meter, on the contrary, indicates an increase in the consumption of energy resources. The mathematical model of the train is adapted to determine the movement parameters of diesel trains and rail buses according to different variable phase coordinates for different drive modes. The practical significance lies in determining the efficiency indicators of the use of different types of rolling stock on the railways of Ukraine, taking into account economic, social and migration factors.
Development of Rare Earth Metal-Modified Heat-Resistant Coatings for Gas Turbine Blades
(Ukrainian State University of Chemical Technology, Dnipro, 2024) Yefanov, V. S.; Gnatenko, M. O.; Laptieva, H. M.; Basov, Y. F.; Sukhyy, Kostyantyn M.; Kovalyov, S. V.; Popov, S. M.
ENG: This paper presents an investigation into the influence of Y-La and Y-Hf-La modifiers on the structure and properties of Ni-Cr-Al consumable cathodes used for heat-resistant coatings on turbine blades via the arc-ion plating method. The study shows that the introduction of these modifiers positively affects the structure formation process of the consumable cathodes. The modifiers contribute to a higher degree of microstructural homogeneity in the cathodes, achieved through the formation of nanosized stabilizing phases between the alloying elements and the rare earth metal groups. This study experimentally confirms that Ni-Cr-Al coatings produced with the Y-La and Y-Hf-La modified cathodes outperform traditional Y-only modified coatings in oxidation tests. Structural analysis of the coatings reveals that samples with Y-Hf-La exhibit greater homogeneity and fewer defects, which is particularly important when depositing coatings with large thicknesses (over 40 µm). It was found that the introduction of the Y-Hf-La complex enables the application of coatings up to 90 µm thick by forming a less defective structure. Additionally, it has been established that Y-Hf-La modification enhances the adhesion of the coating to the substrate and allows for maximum uniformity in the distribution of alloying elements throughout the entire thickness of the applied coating.
Development of Test Methods in the Process of Electrically Conductive Concrete Production
(IOP Publishing Ltd, 2024) Savytskyi, Mykola V.; Pang, Weixiang; Sun, Lijun; Savytskyi, Oleksandr M.; Bordun, Maryna; Li, Yang; Xia, Yanfang; Wang, Haojie
ENG: Prevention of climate change, implementation of sustainable development principles in building industry, creation of Green buildings, Three-zero buildings (zero energy, zero emissions, zero waste), energy independent buildings maybe on the base of Smart Concrete. Electrically Conductive Concrete as type of Smart Concrete have the possibilities to create multifunctional hybrid structures for various purposes. The production of electrically conductive concrete is usually based on the introduction of carbon materials and carbon nanomaterials (CNMs) as electrically conductive fillers into its concrete composition. The theory of conductive percolation is used for design of electrically conductive concrete. To select electrically conductive carbon filler, it is necessary to summarize their electrically conductive characteristics. Today, there is no standard for determining the electrical conductivity of carbon fillers, nor is there a method for designing the composition of electrically conductive concrete; the development of both is imperative. Features of the preparation of electrically conductive concrete with hydrophobic carbon nanoparticles prone to aggregation are indicated. To obtain high quality electrically conductive products an operating system for quality control at the stages of the technological process of manufacturing must be proposed. Homogenization of the electrically conductive filler is very important. It is necessary to propose a method for assessing the stability of an aqueous suspension of a hydrophobic carbon material used for homogeneous distribution of a filler. Due to the lack of a standard, a method for determining the electrical conductivity of concrete is also needed.
Didactic Aspects of Distance Learning in the Conditions of Pandemic and Martial Law
(Dnipropetrovsk State University of Internal Affairs, Dnipro, Ukraine, 2022) Galushko, Olena; Kovalenko-Marchenkova, Yevheniia; Chistyakov, Volodymyr G.
ENG: The article deals with the topical issues of improving the effectiveness of the educational process in higher educational institutions in the conditions of a pandemic and martial law. The evolution of distance learning is considered. Peculiarities of the remote form of education, which functions on the basis of modern psychological and pedagogical and information and communication technologies, have been studied. The peculiarities of the organization of the educational process in higher educational institutions in the context of the pandemic and martial law were analyzed, in particular didactic aspects of the educational process in conditions of danger and increased stress. Special attention is paid to the psychological state of students and ways of reducing stress and activating their attention on the educational process, taking into account the types of information perception (audio, visual, kinesthetic, digital). Ways to improve the distance learning process in the conditions of a pandemic and martial law are proposed.
Effects of Composition on the Structure, Thermal and Some Physical Characteristics of Bi2O3-B2O3-ZnO-SiO2 Glasses
(S.C. Virtual Company of Physics S.R.L, Romania, 2024) Hordieiev, Yu. S.; Zaichuk, A. V.
ENG: The influence of composition on the structure, thermal, and some physical characteristics of bismuth borate glasses, formulated as 55Bi2O3–(35-x-y)B2O3–(5+x)ZnO–(5+y)SiO2 (where 0 ≤ x, y ≤ 15 mol%), was investigated. Comprehensive analyses were conducted using techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), Differential Thermal Analysis (DTA), and Dilatometry. XRD confirmed the amorphous nature of the glass samples, while FTIR spectroscopy revealed that the glasses are primarily composed of BO4, BO3, BiO6, BiO3, ZnO4, and SiO4 structural units. DTA provided further evidence of the samples' glassy state and insights into key temperatures like glass transition (T g), crystallization (T c), and melting (T m). The study finds that substituting B2O3 with SiO2 increases all characteristic temperatures, whereas replacing it with ZnO decreases T g and T c but increases T m. The maximum thermal stability, indicated by a ΔT of 99°C, was observed in the glass with a 55Bi2O3–20B2O3–20ZnO–5SiO2 composition. Dilatometric measurements showed that the investigated glasses have a high coefficient of thermal expansion (10.0–10.7 ppm/°C) values, a low glass transition temperature (345–376°C), and a low dilatometric softening temperature (364–392°C). Additionally, the density and molar volume of the samples were accurately determined.
A Facile Two-Step PVP-Assisted Deposition of Co-Activated Nanosized Nickel Hydroxide Directly on a Substrate for Large-Scale Production of Supercapacitor Electrodes
(MDPI, 2023) Kotok, Valerii; Ondrejka, Peter; Mikolášek, Miroslav; Sojková, Michaela; Novák, Patrik; Gregor, Maroš; Kovalenko, Vadym; Sukhyy, Kostyantyn M.
ENG: The self-decomposition reaction of the nickel ammonia complex was used for the nickel hydroxide formation on the nickel foam with further modification in several ways. The addition of polyvinyl pyrrolidone (PVP) and the electrochemical or chemical activation with cobalt hydroxide was used to modify the formation method. In all cases, structures with Ni(OH)2 nanoflakes were formed. It was found that the flower-like particles of Co(OH)2 were precipitated during chemical activation among the nanoflakes. It was shown that the presence of PVP during the nickel ammonia complex decomposition suppressed the highly branched particles. The absence of the highly branched particles increased the capacitive properties of the formed electrode at high current densities. The highest capacitance in 1408 F/g at 1 A/g was shown for the sample precipitated with the PVP presence and the further chemical activation by cobalt.
Features of the Swelling Kinetics of Polymer Materials in Blended Diesel Fuel
(Lviv Polytechnic National University, Lviv, 2024) Shevchenko, Olena; Popytailenko, Daryna; Ebich, Yurii; Zamikula, Kostiantyn; Sukhyi, Kostiantyn M.; Vytrykush, Nataliya
ENG: The work is devoted to determining the features of the swelling kinetic patterns of polymer materials in contact with blended fuel containing fatty acid esters. Kinetic equations for predicting the behavior of polymer materials in contact with blended fuel at different temperatures were obtained. Peculiarities of the swelling kinetics of polymer materials with different chemical structures in blended diesel fuel were studied. It was found that the process proceeds in two stages for any temperature conditions. The effect of fatty acid esters in the composition of blended diesel fuel on the stability of polymer materials depending on their structure and temperature factor was determined. An approach to the selection of polymer materials resistant to the effects of fatty acid esters is proposed. The patterns of changes in the swelling resistance of polymer materials upon contact with blended diesel fuel, depending on their structure, were determined.
Fusible Glass-Crystalline Binder in the Spodumene–Manganese Cordierite System
(Ukrainian State University of Chemical Technology, Dnipro, 2024) Polozhaj, S. G.; Zaichuk, Oleksandr V.; Polozhaj, A. G.
ENG: Low-melting glass-crystalline materials with a low temperature coefficient of linear expansion (TCLE) are widely used in various engineering fields. These materials are utilized for joints, protective coatings, additives in sintering of ceramic materials, including as matrices for high-strength dispersion-reinforced materials based on oxygen-free silicon compounds. This paper presents the results of a study on glass-crystalline materials in the pseudo-binary spodumene–manganese cordierite system. Based on experimental data, a fusibility diagram was constructed. Crystalline phases formed during the cooling of the glass melts were identified using X-ray phase analysis and their crystallization tendency was evaluated. It was found that the crystallization ability of the glasses decreases with an increasing content of manganese cordierite. The most promising, low-melting glass composition was identified, with a LiAlSi2O6:Mg2Al4Si5O18 ratio of 30:70 wt.%. The glass formation temperature for this compostion lies in the range of 1200–1250 oC, and the practical melting temperature is 1450 oC. The synthesized glass exhibits softening and intensive crystallization onset temperatures of 760 oC and 960 oC, respectively. The TCLE of the glass is 34.9⋅10–7 oC–1. The primary crystalline phase, β-spodumene, forms bundles of needle-like crystals 10–15 μm in length within the residual glass phase, reducing the material’s TCLE to 20.9⋅10–7 oC–1. The developed material shows potential as a glass-crystalline binder for producing high-strength ceramic materials (wear-resistant and impact-resistant) based on SiC and Si3N4 with reduced sintering temperatures.
Glass-Ceramic Binder of Cordierite Composition for Low-Temperature Sintering of High-Strength Ceramic Materials Based on Oxygen-Free Silicon Compounds
(Ukrainian State University of Chemical Technology, Dnipro, 2024) Polozhaj, S. G.; Zaichuk, Oleksandr V.; Polozhaj, A. G.; Amelina, O. A.; Rudnieva, L. L.
ENG: The mechanical properties of composite ceramic materials obtained based on oxygenfree silicon compounds are largely determined by the properties of the glass binder. This paper presents the results of studies aimed at determining the most fusible glass in the pseudo-binary system 2MgO⋅2Al2O3⋅5SiO2–2MnO⋅2Al2O3⋅5SiO2 with a high tendency to crystallize as a glass-ceramic binder for low-temperature sintering of high-strength ceramic materials based on oxygen-free silicon compounds. The crystallization tendency of the experimental melts decreases with an increase in in the content of manganese cordierite, as confirmed by X-ray and infrared spectroscopic studies. Based on experimental studies, a melting diagram was constructed, which was used to determine the ratio between magnesium cordierite and manganese cordierite (50:50 wt.%), ensuring a minimum melt temperature of 1275 oC. The melting point of the glass of the specified composition is 1450 oC. The synthesized glass is characterized by a softening point of 800 oC and crystallizes intensively at 1030 oC. The thermal coefficient of linear expansion of the crystallized glass samples is 20.8⋅10–7 oC –1. X-ray diffraction and electron microscopic studies have shown that the developed glass is almost completely crystallized during heat treatment for 2 hours, forming a cordierite solid solution 2(Mg,Mn)O⋅2Al2O3⋅5SiO2. The size of the cordierite phase crystals ranges from 0.5 to 3.0 µm. Due to its fusibility and high crystallization tendency, the developed glass, can be proposed as a promising glassceramic binder for the production of high-strength ceramic materials (wear and impact resistant) based on SiC and Si3N4 with reduced sintering temperatures.
How Much Is Needed? Discussion on Benchmarks for Primary Energy Input and Global Warming Potential Caused by Building Construction
(MDPI, Basel, Switzerland, 2025) Rabenseifer, Roman; Kalivodová, Martina; Kononets, Yevhen; Mahas, Nataliia; Minarovičová, Katarína; Provazník, Robert; Bordun, Maryna; Shekhorkina, Svitlana; Savytskyi, Mykola V.; Savytskyi, Oleksandr M.; Semko, Volodymyr
ENG: The operational energy efficiency of new buildings in the EU should be at the level of ultra-low or near-zero energy buildings. It is therefore relatively difficult to achieve further energy savings. However, the pre-operational phase—raw material sourcing, manufacturing, transportation, and construction—offers significant energy savings and greenhouse gas reduction opportunities, referred to as embodied energy and equivalent CO2 emissions. Unlike operational energy, no standard or legislative criteria have yet been established for embodied energy. Setting maximum embodied energy values converted to the unit of heated building area, accounting for building shape factor, and differentiating between high-mass and lightweight constructions are proposed. This study illustrates assessing environmental indicators based on building shape, highlighting the necessity of relative assessments over absolute values to favour energy efficiency. It also emphasizes that precise criteria should derive from authentic data collected during the energy certification and building permitting processes. Integrating assessments of embodied energy and operational energy demand facilitates a comprehensive evaluation of buildings’ environmental performance.
Impact of Aluminum Fluoride Addition on Crystallization, Structure and Thermal Properties of Lead Borate Glasses
(S.C. Virtual Company of Physics S.R.L, Romania, 2024) Hordieiev, Yu. S.; Zaichuk, A. V.
ENG: The glass composition (70-x)PbO–(30-y)B2O3–(x+y)AlF3, where x and y ranges from 0 to 20 mol%, were prepared using the conventional melt-quenching-annealing technique. The structural and thermal properties of the glasses were comprehensively analyzed using techniques like Differential Thermal Analysis (DTA), Dilatometry, Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). XRD confirmed the amorphous, non-crystalline structure of the glasses. The glass network was found to be composed of structural units such as PbO4, BO4, BO3 and AlO6 using FTIR spectroscopy. FTIR analysis revealed significant structural changes, including the transformation of BO4 to BO3 units and the increase in non-bridging bonds, particularly with higher AlF3 content. DTA was instrumental in determining characteristic temperatures, such as the glass transition, melting, and peak crystallization temperatures, along with glass stability parameters (∆T, Hr, Tgr) for all samples. The study found that the addition of AlF3 led to a decrease in these characteristic temperatures when replacing B2O3, but an increase when replacing PbO. Variations in the density and thermal expansion of the lead borate glass were observed upon the addition of AlF3, decreasing when substituting for PbO and increasing when substituting for B2O3. These findings provide insights into the properties of oxyfluoride glasses, paving the way for future optimization in their composition for varied applications.
The Influence of Solid-State Polycondensation of Polyethylene Terephthalate on Its Rheological Properties
(Ukrainian State University of Chemical Technology, Dnipro, 2024) Chervakov, Denys O.; Ved, V. V.; Fedan, V. V.; Sukhyy, Kostyantyn M.; Chervakov, Oleh V.
ENG: The influence of solid-state polycondensation conditions on the rheological properties of polyethylene terephthalate was determined. Mathematical models describing the dependence of the melt flow rate of both virgin and recycled polyethylene terephthalate on the time and temperature of the solid-state polycondensation process were developed. A correlation between the melt flow rate and the average molecular weight of polyethylene terephthalate was demonstrated. Experimental studies showed that conducting solid-state polycondensation of recycled polyethylene terephthalate at temperatures ranging from 130 оC to 160 оC for 3 hours produces polymeric materials with higher molecular weight and, consequently, improved performance properties.
Innovative Technological Concept for the Production of High-Density Cathodes for Lithium Reserve Power Sources with Increased Specific Energy
(Ukrainian State University of Chemical Technology, Dnipro, 2024) Markevych, O. V.; Polishchuk, Y. V.; Zinin, V. V.; Vavilon, K. I.; Sukhyy, Kostyantyn M.
ENG: This paper presents an innovative technological concept that significantly enhances the specific energy (both gravimetric and volumetric) of primary lithium power sources. A composition and laboratory-scale process for manufacturing composite cathodes with minimal electrochemically inactive («ballast») components have been developed. The proposed approach enables the production of high-density cathodes without significantly reducing their porosity. The composite cathodes were tested in disc-shaped primary power sources with dimensions of 2325 (23 mm in diameter and 2.5 mm in height). The effect of graphene content in the cathode mass on the discharge voltage of the cells was investigated. It was demonstrated that a graphene content of 3 % by weight of MnO2 in the cathode mass increases the average discharge voltage of the cells from 2.1 V to 2.5 V at a discharge current of 1 mA. Testing at a discharge current of 1 mA revealed that the capacity of the developed cells exceeds that of the best commercial counterparts by at least 40 %.

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